<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <title>Document</title>
</head>
<body>

<div id="app"> 
  <h2>{{counter}}</h2>
  <!-- <h2 v-bind:title></h2>
  <h2 :title></h2> -->
  <!-- <button v-on:click="counter++">+</button>
  <button v-on:click="counter--">-</button> -->
  <!-- <button v-on:click="increment">+</button>
  <button v-on:click="decrement">-</button> -->
  <button @click="increment">+</button>
  <button @click="decrement">-</button>
</div>
  
<script src="../js/vue.js"></script>
<script>
  const app = new Vue({
    el: '#app',//用于挂载要管理的元素
    data: {
      counter: 0
    },
    methods: {
      increment() {
        this.counter++
      },
      decrement() {
        this.counter--
      }
    }
  })
</script>

</body>
</html>